Air brake



1.949 E. c. VROMAN 2,491,344

AI?! BRAKE Filed June 11, 1946 TO MA 1N RES.

T0 BRAKE PIPE INVENTOR. Erwin C.Vroma.n

AHornegs Patented Dec. 13, 1949 AIR BRAKE Erwin C. Vrornan, Water-town,assignot to I The New York Air Brake Company, a corporation of NewJersey Application June 11, 1946; Serial No. 375,833

4 Claims.

This invention relates to air brakes and particularly to a device whichindicates with reasonable certainty whether the brakes on the rear carsof a train have or have not released.

With modern heavy locomotives used to pull long trains there is need fora device which will indicate to theengineer, during a release of thebrakes, the condition of brakes at the rear end of the train. The resultis secured, according to the invention, by sensing the rate of flow ofair to the brake pipe while the engineer's brake valve is in runningposition. i

It has the advantage that rate of flow is determined by measuring thepressure drop through the engineers brake valve, so that no specialorifices or other flow restricting means are interposed in the path offeeding flow to the brake pipe.

The device is adjustable through a suflicient range to permit the sameindicating mechanism to be used with different types of engineers brakevalves (such as No. 6 and No. 8) and different iced valves, such as theF and the M types.

The indicator responds also to the unusual de mands for air such aswould be occasioned by an open back up valve or an unusually heavybrakepipe leak.

The invention will now be described as. used with an H fi brake valveand an F feed valve,

each of which is an accepted standard on Amerii can railroads.

In the drawing, the single figure shows the pressure responsive devicein section, with connections to the signal, the brake valve, the feedvalve and the brake pipe.- sponsive device is drawn on as large a scaleaspraeticable and the brake system parts are drawn in miniature and inelevation since their internal construction is well known.

The main reservoir connection I leads to the H-6 brake valve 2 and fromthe latter leads the brake pipe 3 with the usual double-heading cock 4.From main reservoir pipe I a branch 5 leads to the model F feed valve 6,and. from the feed 'yalve, line 1 leads to the engineers brake valve ,2.The line 8 is the external pressure transmitting connection from brakepipe 3 to feed valve 6, and is a familiar distinguishing characteristicof the model F valve. The knob 9 is the pressure adjusting member of thefeed valve.

The parts and connections so far described are standard on Americanrailroads, as persons skilled in the art will recognize.

The signal device comprises a pressure operated switch and appropriatesignal controlled thereby,

The pressure rethe switch responding to the pressure differential causedby resistance to flow through the engineers brake valve (in runningposition) from the feed valve outlet to the brake pipe. Thisdifferential is approximately proportional to the rate of flow.

The housing of the pressure switch comprises a body H, a top cap 12 andbottom cap l3. Cap I2 is sealed by a gasket Id and held by machinescrews, one of which appears at M Mounted in cap l2 aretwo binding postsl5 insulated and sealed at ii. p v

Clamped at its margin between body II and cap I3 is a combined gasketand diaphragm I1. A- thrust-plate l8 reacts upward on the central areaof the diaphragm and is loaded by a coil compression spring I 9. Thespring is sustained by spring seat 2| which is adjustable by turningthrust screw 22. The latter is locked and sealed air tight by cap nut23.

The upper face of diaphragm l'l carries at its center a thrust disc 24and this reacts upward on a plunger 25 guided vertically in bracket 26formed integrally with body ll.

Fixedly supported within body H is an electric switch indicated by thenumeral 21 applied to its housing. This should be a sensitive snap typeswitch preferably biased to close, and consequently opened by upwardmotion of plunger 25. Such switches will control substantial currentsand will function in response to motions of a few thousandths of aninch.

As arranged; switch 21 closes on downward motion of plunger 25 which isinterposed between disc 24 and the actuating member of the switch. Theswitch terminals are electrically connected with thebindiiig posts It asindicated and;

through them to a circuit including a source of current 28, shown as abattery, and a signal 29, shown as a lamp. Any suitable current source,and any preferred signal, audible, visible or other, could besubstituted.

With an H-6 brake valve, the space within body H (i. e., the space abovethe diaphragm) is connected by a pipe 3| with'line I, and the spacewithin cap l3 (i. e., the space below the diaphragm) is connected bypipe 32 to the brake pipe 3 at a point between the brake valve 2 and thedouble-heading cock 4.

With a No. 8 valve connection 3| would lead to the feed valve supplypassage at the brake valve pedestal, usually designated as connection 20and connection 32 would conveniently lead to the brake pipe gageconnection. These connections are functionally the same as thoseillustrated.

During release when flow to the brake pipe is rapid, brake pipe pressurewill be sufliciently below pressure at the feed valve outlet to causediaphragm I! to move down far enough to permit switch 21 to close andcause light 29 to glow. Assuming no excessive losses from the brake pipeby leakage or the like, releasing movement of the AB valves or triple'valve's at the'end of the train will reduce the demand for air, and byreducing the pressure drop incident to air flow will allow diaphragm I!to rise and open switch 21.

Thus, extinction of light 29 is caused to signal release of end brakes.It is considered better to have the light burn to indicate that releasehas not reached the end of the train. Reversal of the switch actionwould cause the light to light up when release action reaches the end ofthe train-a possible alternative arrangement.

The device is calibrated for any particular brake valve by adjustingscrew 22. It'will operate satisfactorily with an M feed valve, but itsaction is more positive with an F feed valve because of the more preciseoperating characteristics of that valve.

The general principle of the invention involves the sensing of apressure differential occasioned by flow through the engineers brakevalve during release. This can be done in various ways, of which thesimplest now known has been chosen for illustrative purposes, butwithout limiting implication. The scope of the invention will be definedsolely by the claims.

What is claimed is:

l. The combination of an automatic air brake system comprising anengineers brake valve, a feed valve connected to supply air to the brakevalve and a normally charged brake pipe connected to be charged andvented by the brake valve; and means for indicating at or near theengineers brake valve conditions existing'at the remote end of the brakepipe, said indicating means comprising a device arranged to sensethecharacteristic of running condition with the system fully charged,and adjustable means for selecting the differential pressure at whichsaid signal functions.

3. The combination of an automatic air brake system comprising anengineers brake valve, a feed-valve connected to supply air to the brakevalve, and a normally charged brake pipe connected to be charged andvented by the brake valve; and means for indicating ator near theengineers brake valve conditions at the remote end of the brake pipe,said indicating means comprising, a pressure motor responsive to thevpressure differential between the feed valve discharge and the brakepipe; means imposing a definite yielding bias on said motor in thedirection to assist brake pipe pressure; and a signal operable byshifting of said motor in the direction of said bias.

4. The combination of an automatic air brake system comprising anengineers brake valve, a feed-valve connected to supply air to the brakevalve, and a normally charged brake pipe connected to be charged andvented by the brake valve; and means for indicating at or near theengineers brake valve conditions at the remote end of the brake pipe,said indicating means comprising a diaphragm subject in oppositedirections to the pressure existing at a point between the feed valveand engineers brake valve and to the pressure simultaneously existing inthe brake pipe; adjustable means for yieldingly loading said diaphragmin a direction to assist the action of brake pipe pressure; an electricswitch arranged to be opened and closed by motion of said diaphragm; anda circuit including a signal'controlled by said switch.

ERWIN C. VROMAN.

REFERENCES CITED UNITED STATES PATENTS Name Date Campbell Nov. 28, 1933Number

